Soft chewable tablets

ABSTRACT

The present invention relates to a compressed, chewable tablet containing at least one active ingredient, a water-disintegratable, compressible carbohydrate and a binder. These components are dry blended and compressed into convex-shaped tablet having a hardness of about 2 to about 11 kp/cm 2  and friability less than 1%.

This is a continuation of prior application Ser. No. 09/880,179, filedJun. 13, 2001, now U.S. Pat. No. 6,471,991, which is a continuation ofapplication Ser. No. 09/135,723, filed Aug. 18, 1998, which is now U.S.Pat. No. 6,270,790.

FIELD OF THE INVENTION

The present invention relates to soft, convex-shaped compressed chewabletablets and a process for preparing such tablets.

BACKGROUND OF THE INVENTION

Chewable tablets are widely used in the pharmaceutical industry forpatients, such as children, who have who have difficulty swallowingconventional tablets or capsules. Children's TYLENOL® Chewable Tablesare an example of a pediatric chewable acetaminophen tablet sold in theUnited States. These tables are packaged in bottles and have a flatface, beveled edge shape. Samples of these tablets obtained from retaillocations had hardnesses (average of ten tablets) ranging from 5.3–13.1kp or normalized hardnesses of 12.3–30.5 kp/cm².

Many comercially avaialable pediatric chewable tablets contain activeingredients which are coated with polymers to mask their unpleasanttaste. However, the forces used to compress these tablets can fracturethe polymer coatings, which reduces the effectiveness of thetastemasking system.

Rapidly disintegrating dosage forms, such as those described in U.S.Pat. No. 5,464,632, issued Nov. 7, 1995, are also available forpatients, particularly aged and pediatric patients, having difficlutiesswallowing tablets and caplets. However, rapidly disintegrating dosageforms currently available are highly friable, and require the use ofspecial handling and costly packaging, e.g., specially designed blisterpacks, to prevent breakage or chipping of the tablets. These limitationssignificantly increase the product cost.

Tablet shape also affects tablet friability. T. Chakrabarti et al. inThe Indian Journal of Pharmacy, Vol. 38, No. 3, pp. 62–65 (1975)disclose that lower friability was observed in beveled flat tabletsfollowed by standard convex and plain flat tablets. Similarily, K.Sugimori et al. in Powder Technology, Vol. 58, pp. 259–264 (1989) reportthat capping occurs more often in convex-shaped tablets than flat facedtablets.

A need, therefore, exists for compressed, chewable tablets havingimproved taste, but which exhibit low friability so that they may beprocessed with standard bulk handling equipment and packaged in bottles.

SUMMARY OF THE INVENTION

The present invention provides a compressed, chewable tablet containingat least one active ingredient, a water-disintegratable, compressiblecarbohydrate and a binder. These components are dry blended andcompressed into a convex-shaped tablet having a hardness of about 2 toabout 11 kp/cm². The tablet has a friability of less than 1%.

In a preferred embodiment of the present invention, the compressed,chewable tablet is prepared by dry blending the active ingredient,water-disintegratable, compressible carbohydrate and binder, and thencompressing into a convex-shaped tablet having a hardness of about 2 toabout 11 kp/cm². If the active ingredient has an objectionable taste, itis coated with a taste masking composition.

Compressing at reduced force reduces fracture of the coating used formasking the unpleasant taste of the active ingredient. Theseconvex-shaped, chewable tablets are softer that conventional chewabletablets, which results in improvements in product taste, mouthfeel, andease of chewing.

The convex tablet geometry significantly reduces tablet friability at agiven compression force. This reduction in tablet friability allows forthe use of lower compression forces and lower tablet hardness, whilemaintaining the ability to process the tablets with conventional bulkhandling equipment and package them in conventional bottles.

BRIEF DESCRIPITON OF THE DRAWINGS

FIGS. 1 a and 1 b are front and side views, respectively, of a bi-convextablet of the present invention.

FIG. 2 is a graph of friability (wt % loss) vs. hardness (kp/cm²) for atablet produced with flat face, beveled edge tooting (control) and aconvex tablet of the present invention produced with concave tooling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The compressed, chewable tablets of the present invention comprise atleast one active ingredient, a water-disintegratable, compressiblecarbohydrate, and a binder. These ingredients are dry blended and thencompressed into a convex-shaped tablet having a hardness of about 2 toabout 11, preferably about 5 to about 8.5, kp/cm². Tablet friability isalso preferably less than

Tableting machines, preferably those capable of applying separatepre-compression and main compression forces, are used to compress theingredients into tablets. Since the ingredients are dry blended,water-soluble, as well as water-insoluble, active ingredients can beused in the tablet. If the active ingredients have an objectionabletaste they may be coated with a taste masking composition.

The water-disintegratable, compressible carbohydrate used in the presentinvention includes carbohydrate materials conventionally used intablets. The carbohydrates facilitate the breakup of the dosage formafter oral administration, and are described in Lieberman et al.,Pharmaceutical Dosage Forms, Marcel Dekker, Inc., New York, 2 Ed. Vol.1, pp. 205–209 (1990), which is hereby incorporated by reference.Preferred water-disintegratable, compressible carbohydrates includemannitol, sorbitol, maltitol, dextrose, sucrose, xylitol, lactose, andmixtures thereof.

The binder in the present invention is used to add cohesiveness to theformulation, thereby providing the necessary bonding to form a cohesivemass or compact upon compression. These binders are conventionally usedin direct compression tablets and are described in Lieberman et al.,Pharmaceutical Dosage Forms, 2 Ed., Vol. 1, pp. 209–214 (1990), which ishereby incorporated by reference. Preferred binders include cellulose,cellulosic derivatives, polyvinyl pyrrolidone, starch, modified starch,and mixtures thereof, and, in particular, microcrystalline celluloseavailable from FMC Corp. under the trademark AVICEL® PH 101.

The tablets of the present invention are used to orally administer awide variety of active ingredients. Suitable active ingredients includepharmaceuticals, minerals, vitamins and other nutraceuticals. Suitablepharmacuticals include analgesics, decongestants, expectorants,antitussives, antihistamines, gastrointestinal agents, diuretics,bronchodilators, sleep-inducing agents and mixtures thereof. Preferredpharmaceuticals include acetaminophen, ibuprofen, flurbiprofen,naproxen, aspirin, pseudoephedrine, phenylpropanolamine,chlorpheniramine maleate, dextromethorphan, diphenhydramine, famotidine,loperamide, ranitidine, cimetidine, astemizole, terfenadine, terfenadinecarboxylate, cetirizine, mixtures thereof and pharmaceuticallyacceptable salts thereof.

The active ingredient(s) are present in the tablet in a therapeuticeffective amount, which is an amount that produces the desiredtherapeutic response upon oral administration and can be readilydetermined by one skilled in the art. In determining such amounts, theparticular compound being administered, the bioavailabilitycharacteristics of the ingredient, the dose regime, the age and weightof the patient, and other factors must be considered.

If the active ingredient has an objectionable taste, a coated particlecontaining the active ingredient coated with a taste masking coating isemployed. The active may be coated with taste masking coatings known inthe art, such as those described in U.S. Pat. No. 4,851,226, issued Jul.25, 1989, to T. W. Julian, et al.; U.S. Pat. No. 5,075,114, issued Dec.24, 1991 to E. J. Roche; and U.S. Pat. No. 5,489,436, issued Feb. 6,1996, all of which are hereby incorporated by reference. Commerciallyavailable taste masked active ingredients may also be employed. Forexample, acetaminophen particles which are encapsulated withethylcellulose or other polymers by a coaccervation process may be usedin the present invention. Coaccervation-encapsulated acetaminophen maybe purchased commercially from Eurand America, Inc. Vandalia, Ohio, orfrom Circa Inc., Dayton, Ohio.

As used in the present invention, “coated particle” refers to a solidactive ingredient in the form of a crystal or particle, an agglomerateof individual particles, or a granuled particle, which has beenencapsulated with a the taste masking composition, either by filmcoating or by another process such as coaccervation. The tablet mayprovide for immediate or sustained release of the active.

Taste masking compositions suitable for use as coatings are provided inthe following table:

Polymer System Coat Level¹ Polymer Ratio² Cellulose Acetate/PVP 5–60%90/10 to 60/40 Cellulose Acetate 5–60% 90/10 to 60/40 Butyrate/PVPCellulose Acetate/HPC 5–60% 90/10 to 50/50 Cellulose Acetate 5–60% 90/10to 50/50 Butyrate/HPC Cellulose Acetate/ 8–60% All ratios EUDRAGIT E 100Cellulose Acetate Butyrate/ EUDRAGIT E 100 8–60% All ratios EthylCellulose/PVP 8–60% 90/10 to 60/40 Ethyl Cellulose/HPC 8–60% 90/10 to50/50 Ethyl Cellulose/EUDRAGIT 8–60% All ratios E 100 HPC 10–60%  NA HEC10–60%  NA EUDRAGIT E 100 10–60%  NA HPMC 10–60%  NA HEC/HPMC 10–60% All ratios HPC/HPMC 10–60%  All ratios HEC/HPC 10–60%  All ratios2-vinyl pyrridine styrene 10–60%  NA co-polymer CA/2-vps 8–60% Allratios CAB/2-vps 8–60% All ratios Ethyl Cellulose/2-vps 8–60% All ratiosCellulose Triacetate/PVP 8–60% 90/10 to 60/40 Cellulose Triacetate/HPC8–60% 90/10 to 50/50 Cellulose Triacetate/ 8–60% All ratios EUDRAGIT E100 ¹Percent by weight of the coated particle in a dried state. ²Byweight. PVP—polyvinylpyrrolidone HPC—Hydroxypropyl celluloseHEC—Hydroxyethyl cellulose HPMC—Hydroxypropylmethyl celluloseCA—Cellulose Acetate CAB—Cellulose Acetate Butyrate 2-VPS—2-Vinylpyridine styrene EUDRAGIT ™ E-100—methylaminoethyl-methacrylate andneutral methacrylic acid esters available from Rohm Pharma GmbH,Germany.

Substantially all of the active ingredient or granulated activeingredient should be coated with a layer of a taste masking compositionhaving a thickness of about 3 to about 10 microns. The coating should besubstantially free of cracks, holes or other imperfections when examinedunder a scanning electron microscope at 100–500x.

If taste masking is necessary, the active ingredient is preferablycoated with a blend of a first polymer selected from the groupconsisting of cellulose acetate and cellulose acetate butyrate and asecond polymer selected from the group consisting of polyvinylpyrrolidone and hydroxypropyl cellulose. The weight ratio of the firstpolymer to the second polymer in this blend is within the range of about90:10 to about 50:50 and preferably about 90:10 to about 70:30.

The blend of first and second polymers may be coated directly onto thepure active ingredient or may be coated onto a granulated particlecontaining the active. In the case of a granulated particle, such as arotogranulated particle, the active will constitute from about 5 toabout 90 weight percent of the particle, with the remainder being thebinder or filler. Suitable binders for the granulated particles includepolyvinyl pyrrolidone, hydroxypropylmethyl cellulose, hydroxypropylcellulose, and other pharmaceutically acceptable polymers. Fillerssuitable for use in such granulated particles include lactose,confectioner's sugar, mannitol, dextrose, fructose, otherpharmaceutically acceptable saccharides and microcrystalline cellulose.

The coated particles may be prepared by spraying an organic solventsolution of the polymeric blend onto the active ingredient, or agranulated particle containing the active ingredient, in a fluidizedbed, such as a Wurster coater or a rotogranulator. A wide variety oforganic solvents may be used to prepare the solution of the polymericblend. For example, a preferred solvent is a mixture of acetone andmethanol, but other solvent systems may be employed, including methylenechloride, methylene chloride-methanol, acetone-ethyl acetate,toluene-ethanol and acetone-ethanol. Generally, the proportion of thepolymer blend in the solvent solution will be within the range of about5 to about 20, preferably about 8 to about 15, weight percent, dependingon the solvent and other similar considerations.

When a fluidized bed coating operation is used, air, which may beheated, passes through a bed of the active ingredient solids to fluidizethem, and the solution of the polymeric blend is sprayed onto thefluidized bed and thereby coats the active. The air passing through thebed dried the coating onto the active ingredient, so that a dry coatedgranule is obtained.

Conventional fluidized bed coating equipment may be used in the presentinvention to coat the active ingredient or the rotogranulated particlecontaining the pharmaceutical. This equipment includes Wurster fluid-bedcoaters, where the solution of the polymer blend is sprayed from thebottom of the chamber, and a rotogranulator, where the solution of thepolymer blend is tangentially sprayed. These coating operations arefurther described in Lieberman et al., Pharmaceutical Dosage Forms,Marcel Dekker, Inc., New York, Vol. 3, pp. 138–150 (1990), which ishereby incorporated by reference.

The coated particle, in a dried state, generally contains about 5 toabout 60, preferably about 10 to 40, weight percent of the blend of thefirst and second polymers. The exact proportions of the coating to theactive ingredient can, however, vary depending upon the level of tastemasking required and whether a sustained or immediate release of theactive is desired. Larger proportions of the coating tend to provide asustained release effect and enhance taste masking.

The tablet may also contain ingredients other than the coated particles,carbohydrate and binder. The additional ingredients include sweeteners,such as aspartame, acesulfame potassium, sucralose and saccharin; andlubricants, such as magnesium stearate, stearic acid, talc, and waxes.The dosage form may also incorporate pharmaceutical acceptableadjuvants. Such adjuvants, include, for example, preservatives, flavors,antioxidants, surfactants, and/or colors.

The tablets, on a dry basis, generally comprise from about 0.1 to about60, preferably about 12 to about 25, percent by weight of the activeingredient; from about 30 to about 90, preferably about 40 to about 65,percent by weight of the water-disintegratable, compressiblecarbohydrate material; from about 1 to about 30, preferably about 5 toabout 20, percent by weight of the binder; from about 0.1 to about 5,preferably about 0.5 to about 1.5, percent by weight of the lubricant;from 0 to about 5, preferably about 0.1 to about 3.0, percent by weightof the sweetener; from 0 to about 5, preferably about 0.2 to about 2.0,percent by weight of the flavor; and from 0 to about 5, preferably about0.01 to about 0.4, percent by weight of the color.

The unit weight of the tablet will vary depending on the dosage of theactive ingredient. The unit weight will generally range from about 250to about 1000 mg. A typical dosage form may contain:

Ingredient Unit Wt. (mg) Active Ingredient 0.5–600  CompressibleCarbohydrate 80–900 Binder 10–200 Lubricant 1–15 Sweetener 0–30 Flavor0–20 Color 0–10

If taste masking is required, coated particles of the active ingredientare prepared using the aforementioned techniques. The particle size ofthe coated particles, as well as the remaining components, is generallyless than 600 microns. The components of the tablet are then dry mixedto form a uniform powder blend. The blend is then compressed into atablet of the desired hardness using conventional compression tabletingtechniques.

In a preferred embodiment of the invention, the compressed, chewabletablet has a convex or bi-convex shape and is relatively soft so as toprovide good mouthfeel and taste and ease of chewing. Generally, thetablet will have a diameter of about 7 to about 19, preferably about 9to about 13, mm and a thickness of about 2 to about 12, preferably about3 to about 8, mm.

FIGS. 1 a and 1 b are, top and side views, respectively, of a bi-convextablet 10 of the present invention. The tablet 10 has a pair of opposedface surfaces 12 and a side surface 14. The intersection of the facesurfaces 12 with the side surface 14 defines the edges 16. The facesurfaces 12 for the bi-convex tablet 10 have two radii of curvature, R₁and R₂. The radius of curvature R₁ at the portion of the face surface 12proximate to the edge 16 (minor axis cup radius) is about 0.7 to about7.6, preferably about 2.36, mm. The radius of curvature R₂ at the centerof the tablet face 12 (major axis cup radius) is about 7 to about 76,preferably about 25.2, mm. Alternatively, the minor axis cup radius R₁is about 10% to about 40% of the tablet diameter, while the major axiscup radius R₂ is about 100% to about 400% of the tablet diameter. Theradius of curvature of the face surface of a simple convex tablet of thepresent invention (not shown) is about 5 to about 60 mm, which is about75% to about 300% of the tablet diameter. Tri-convex tablets may also beused.

The external pressure applied by the tablet press during the compressionstep is controlled so that the hardness of the tablet is within therange of about 2 to about 11, preferably about 5 to about 8.5, kiloponds(kp) per sq. cm (cm²). Tablet breaking strength, or hardness, isdependent on cross-sectional area at the tablet breaking point. In orderto compare values across different size tablets, the breaking strengthmust be normalized for the area of the break. This normalized value,expressed in kp/cm² is often referred in the art as tablet tensilestrength. Hardness is measure by conventional pharmaceutical hardnesstesting equipment, such as a Schleuniger Hardness Tester.

During tableting it is preferable to apply the compression forces in twosteps. A pre-compression pressure of about 2 to about 17, preferablyabout 5.5 to about 11.5, kN/cm² is applied. The main compressionpressure of about 3 to about 18, preferably about 7 to about 13, kN/cm²is then applied to complete the compression operation. Alternatively,the tablet may be formed in one compression step using a compressionpressure of about 3 to about 18, preferably about 7 to about 13, kN/cm².

The compressed, chewable tablet has a friability of less than 1%,preferably less than 0.5%. In the present invention, tablet friabilityis determined in accordance with USP Method <1216> Tablet Friability,USP 23 (1995) and is expressed as percent weight loss. As shown in FIG.2, as the hardness of a tablet produced with flat face, beveled edgetooling is reduced, friability increases. However, when the hardness ofa convex tablet of the present invention produced with concave toolingdecreases, friability remains substantially constant. These findings areunexpected in view of the friability reported by Chakrabarti et al. andSugimori et al., supra, for convex tablets.

These findings are significant because the tablets of the presentinvention can be compressed at lower compression forces, but stillmaintain acceptable friability. This results in a softer tablet havingimproved product taste, mouthfeel and ease of chewing. Compressing atreduced forces also reduces the probability of fracturing the coatingused for masking the unpleasant taste of the active ingredient.

Specific embodiments of the present invention are illustrated by way ofthe following examples. This invention is not confined to the specificlimitations set forth in these examples, but rather to the scope of theappended claims. Unless otherwise stated, the percentages and ratiosgiven below are by weight.

EXAMPLE I

This Example provides a formulation for making a compressed, chewablebi-convex tablet containing acetaminophen coated with a blend ofcellulose acetate and polyvinyl pyrrolidone. The weights providedhereinafter are based on a tablet unit weight of 385 mg.

A coating solution containing a blend of cellulose acetate and polyvinylpyrrolidone was prepared in accordance with U.S. Pat. No. 4,851,226 andapplied to acetaminophen until coated acetaminophen particles containingapproximately 11% by weight of coating were obtained. The ratio ofcellulose acetate to polyvinyl pyrrolidone was 85:15.

The coated acetaminophen particles were combined with followingingredients to produce the tablets:

Ingredients Unit Wt. (mg) CA/PVP Coated Acetaminophen Particles 89.9Mannitol (Granular), USP 246.03 Microcrystalline Cellulose, NF 30.0Aspartame, NF 9.0 Color 1.27 Citric Acid, USP 2.1 Flavor 2.3 MagnesiumStearate, NF 4.4 Tablet Weight 385.0Procedure

-   1. Citric acid, aspartame, and color were combined with a portion of    microcrystalline cellulose, and blended until a uniform distribution    of color was obtained. This blend was then passed through a suitable    comminutor.-   2. Magnesium stearate and a portion of the mannitol were combined    and passed through a suitable comminutor.-   3. The remaining mannitol was passed through a suitable comminutor    and then discharged into a blender.-   4. The blends from 1 and 2 above, flavor, coated acetaminophen, and    the remainder of the microcrystalline cellulose were added to the    blender, and blended until uniform distribution of active ingredient    was achieved.-   5. The blend was compressed into bi-convex tablets to the following    specifications on a Fette Model 3090 rotary tablet press:    -   Punches: 10.3 mm diameter, bi-concave having a minor axis cup        radius of curvature of 2.36 mm and a major axis cup radius of        curvature of 25.2mm    -   Pre-compression Force:7.4–8.1 kN (8.5–9.4 kN/cm²)    -   Main Compression Force:8.4–9.1 kN (9.7–10.6 kN/cm²)    -   Thickness: Target 4.5 mm    -   Weight: Target 385 mg    -   Friability*: Target 0.14

The following measurements were made on the tablets:

Physical Property Average of 5 Individuals Weight (mg) 382–389 379–391Hardness (kp/cm²) 6.0–7.4 5.2–8.3 Thickness (mm) 4.44–4.49 4.43–4.52Friability* — 0.11–0.18 *(% wt. loss, 20 tablets)

Bulk tablets were successfully transported between Puerto Rico and NewJersey in 19-gallon fiber drums containing approximately 30 kg oftablets per drum.

EXAMPLE II

This Example describes the friability testing reported in FIG. 2 for thetabled produced with flat face, beveled edge (FFBE) tooling (control)and the convex tablet of the present invention produced with concavetooling. The acetaminophen was coated with the taste masking coatingdescribed in Example I.

The coated acetaminophen particles were combined with followingingredients to produce the FFBE and convex tablets:

Unit Wt. (mg) Ingredients Convex FFBE CA/PVP Coated Acetaminophen 90.790.7 Mannitol (Granular), USP 241.55 226.55 Microcrystalline Cellulose,NF 30.0 30.0 Aspartame, NF 5.0 11.0 Acesulfame Potassium 6.0 — Color0.35 0.35 Flavor 22.5 22.5 Magnesium Stearate, NF 3.9 3.9 Tablet Weight400.0 385.0

The ingredients were blended and compressed into tablets on a ManestyBetapress at different hardness levels by changing the compressionforces. The following specifications were used:

Convex

-   -   Punches: Round, no land, standard concave 13/32 inch (10.3        mm)×0.038 inch cup depth    -   Hardness Range: 1.5–6.0 kp    -   Weight(10 tablets): 4.0 g (Range 3.85–4.15 g)        FFBE    -   Punches: 10 mm round flat faced, beveled edge    -   Hardness Range: 1.5–6.0 kp    -   Weight (10 tablets): 3.85 g (Range 3.75–3.95 g)

The friability of the tablets was measured in accordance with TabletFriability <1216>, USP 23 (1995). Friabilty in wt % was then plottedagainst normalized hardness or tablet tensile strength in FIG. 2.

EXAMPLE III

Tastemasked acetaminophen particles, prepared in the manner described inExample I, were combined with the following ingredients to producecompressed, chewable tablets, using the process described below:

Ingredients Unit Wt. (mg) CA/PVP Coated Acetaminophen Particles 90.7Mannitol (Granular), USP 243.96 Microcrystalline Cellulose, NF 30.0Aspartame, NF 11.0 Color 0.04 Citric Acid, USP 2.1 Flavor 3.3 MagnesiumStearate, NF 3.9 Tablet weight 385.0Procedure

-   1. All ingredients except magnesium stearate were combined in a PK    blender, and blended for 10 minutes. The magnesium stearate was    added to the blender and blending was continued for an additional 5    minutes.-   2. Tablets were compressed to the following specifications on a    Manesty Betapress using 13/32-inch diameter, round bi-concave    tooling having 2.36 mm minor axis cup radius and 25.2 mm major axis    cup radius:    Target    -   Pre-compression Force 0–0.1 kN (0–0.12 kN/cm²)    -   Main Compression Force 6.5–6.9 kN (7.5–8.0 kN/cm²)    -   Weight (average of 10): 385 mg    -   Thickness (average of 5): 4.63 mm    -   Hardness (average of 5): 3.0 kp(6.5 kp/cm²)        The following measurements were made on the tablets:

Physical Property Range Weight (average of 10) 383.5–386.7 mg Hardness(average of 5)  2.90–3.06 kp (6.27–6.61 kp/cm²) Thickness (average of 5) 4.62–4.66 mm

A sensory preference test was conducted among 130 adults who tastedthese tablets in comparison with Children's TYLENOL® 80 mg AcetaminophenChewable Tablets (having an average hardness of 5.5 kp or 13.4 kp/cm²)obtained from retail locations. The tablets in this example werepreferred over the commercial product by 77% of the participants, while22% preferred the commercial product. The tablets in this example wereperceived as less bitter, more sweet, and having more pleasant taste andmouthfeel than the commercial product.

Various modifications can be made from the above-described embodimentswithout departing from the spirit and scope of the present invention.

1. A product produced by the process, comprising the steps of: drymixing at least one taste-masked coated active ingredient selected fromacetaminophen, a water-disintegratable, compressible carbohydrate and abinder; and compressing the mixture into a tablet having convex shapedopposed face surfaces and a hardness of about 2 to about 11 kp/cm². 2.The product of claim 1 wherein said mixture is compressed to a tablethardness of about 5 to about 8.5 kp/cm².
 3. The product of claim 1wherein said taste masking coating comprises a blend of a first polymerselected from the group consisting of a cellulose acetate and celluloseacetate butyrate and a second polymer selected from the group consistingof polyvinyl pyrrolidone and hydroxypropyl cellulose, wherein the weightratio of the first polymer to the second polymer is within the range ofabout 90:10 to about 50:50.
 4. The product of claim 1 wherein thecompressible carbohydrate is selected form the group consisting ofmannitol, sorbitol, maltitol, dextrose, sucrose, xylitol, lactose, andmixtures thereof.
 5. The product of claim 1 wherein the binder isselected form the group consisting of cellulose, cellulosic derivatives,polyvinyl pyrrolidone, starch, modified starch and mixtures thereof. 6.The product of claim 1 wherein said face surfaces have a bi-convex ortri-convex shape.
 7. The product of claim 6 wherein said tablet hasbi-convex shaped face surfaces and a minor axis cup radius of about 10to about 40 percent of the tablet diameter and major axis cup radius ofabout 100 to about 400 percent of the tablet diameter.
 8. The product ofclaim 1 wherein said tablet has a friability of less than about 1%. 9.The process of claim 8 wherein said friability is less than about 0.5%.10. The process of claim 1 wherein a pre-compression force is applied tosaid mixture before the application of a main compression force.